EN ISO 4491-3:2006
(Main)Metallic powders - Determination of oxygen content by reduction methods - Part 3: Hydrogen-reducible oxygen (ISO 4491-3:1997)
Metallic powders - Determination of oxygen content by reduction methods - Part 3: Hydrogen-reducible oxygen (ISO 4491-3:1997)
Migrated from Progress Sheet (TC Comment) (2000-07-10): Revision in ISO/TC 119 followed by UAP
Metallpulver - Bestimmung des Sauerstoffgehaltes durch Reduktionsverfahren - Teil 3: Wasserstoffreduzierbarer Sauerstoff (ISO 4491-3:1997)
Dieser Teil der ISO 4491 legt ein Verfahren zur Bestimmung des wasserstoffreduzierbaren Anteils an Sauerstoff von Metallpulvern mit einem Sauerstoff-Massenanteil von 0,05 % bis 3 % fest.
Das Verfahren ist auf unlegierte, teilweise legierte oder vollständig legierte Metallpulver sowie aus Mischungen von Carbiden und Bindemetallen anwendbar. Es kann nicht angewendet werden auf Pulver mit Gleitmittelzusätzen oder organischen Bindemitteln.
Das Verfahren darf bei Einsatz einer speziellen katalytischen Vorrichtung auf kohlenstoffhaltige Pulver ausgedehnt werden.
Diese Norm ist im Zusammenhang mit ISO 760 und ISO 4491-1 anzuwenden.
Poudres métalliques - Dosage de l'oxygène par les méthodes de réduction - Partie 3: Oxygène réductible par l'hydrogène (ISO 4491-3:1997)
Kovinski praški - Določevanje kisika z metodami redukcije - 3. del: Kisik, ki reducira vodik (ISO 4491-3:1997)
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-januar-2007
.RYLQVNLSUDãNL'RORþHYDQMHNLVLND]PHWRGDPLUHGXNFLMHGHO .LVLNNL
UHGXFLUDYRGLN ,62
Metallic powders - Determination of oxygen content by reduction methods - Part 3:
Hydrogen-reducible oxygen (ISO 4491-3:1997)
Metallpulver - Bestimmung des Sauerstoffgehaltes durch Reduktionsverfahren - Teil 3:
Wasserstoffreduzierbarer Sauerstoff (ISO 4491-3:1997)
Poudres métalliques - Dosage de l'oxygene par les méthodes de réduction - Partie 3:
Oxygene réductible par l'hydrogene (ISO 4491-3:1997)
Ta slovenski standard je istoveten z: EN ISO 4491-3:2006
ICS:
77.160 Metalurgija prahov Powder metallurgy
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD
EN ISO 4491-3
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2006
ICS 77.160
English Version
Metallic powders - Determination of oxygen content by reduction
methods - Part 3: Hydrogen-reducible oxygen (ISO 4491-
3:1997)
Poudres métalliques - Dosage de l'oxygène par les Metallpulver - Bestimmung des Sauerstoffgehaltes durch
méthodes de réduction - Partie 3: Oxygène réductible par Reduktionsverfahren - Teil 3: Wasserstoffreduzierbarer
l'hydrogène (ISO 4491-3:1997) Sauerstoff (ISO 4491-3:1997)
This European Standard was approved by CEN on 9 March 2006.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the Central Secretariat or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,
Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
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© 2006 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 4491-3:2006: E
worldwide for CEN national Members.
Foreword
The text of ISO 4491-3:1997 has been prepared by Technical Committee ISO/TC 119 "Powder
metallurgy” of the International Organization for Standardization (ISO) and has been taken over
as EN ISO 4491-3:2006 by Technical Committee CEN/SS M11 "Powder metallurgy", the
secretariat of which is held by CMC.
This European Standard shall be given the status of a national standard, either by publication of
an identical text or by endorsement, at the latest by October 2006, and conflicting national
standards shall be withdrawn at the latest by October 2006.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary,
Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Endorsement notice
The text of ISO 4491-3:1997 has been approved by CEN as EN ISO 4491-3:2006 without any
modifications.
IS0
INTERNATIONAL
4491-3
STANDARD
Second edition
1997-04-O 1
Metallic powders - Determination of
oxygen content by reduction methods -
Part 3:
Hydrogen-reducible oxygen
Poudres m&//iques - Dosage de I’oxygkne par les mBthodes de
kduction -
Partie 3: Oxyg&ne kductible par I’hydrogkne
Reference number
IS0 449+3:1997(E)
IS0 4491=3:1997(E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide
federation of national standards bodies (IS0 member bodies). The work of
preparing International Standards is normally carried out through IS0
technical committees. Each member body interested in a subject for which
a technical committee has been established has the right to be represented
on that committee. International organizations, governmental and non-
governmental, in liaison with ISO, also take part in the work. IS0
collaborates closely with the International Electrotechnicaj Commission
(IEC) on all matters of electrotechnical standardization.
Draft international Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
International Standard IS0 4491-3 was prepared by Technical Committee
ISOITC 119, Powder metallurgy, Subcommittee SC 2, Sampling and testing
methods for powders (including powders for hardmetals).
This second edition cancels and replaces the first edition (IS0 4491-3:1989),
clauses 7 and 8 of which have been technically revised.
IS0 4491 consists of the following parts, under the general title Metallic
powders - Determination of oxygen content by reduction methods:
- Pat? I: General guidelines
- Part 2: Loss of mass on hydrogen reduction (hydrogen loss)
Part 3: Hydrogen-reducible oxygen
Part 4: Total oxygen reduction-extraction
bY
0 IS0 1997
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronic or mechanical, including photocopying and
microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case postale 56 l CH-1211 Geneve 20 l Switzerland
l nternet central @ iso.ch
x.400 c=ch; a=400net; p=iso; o=isocs; s=central
Printed in Switzerland
ii
@ IS0 IS0 4491-3: 1997(E)
Introduction
The International Standard which the first edition of this part of IS0 4491
(IS0 4491-3: 1989) replaced (IS0 4993: 1981) described one particular
arrangement of apparatus and procedure for the determination of hydrogen-
reducible oxygen. However, it has since been established that other
schemes will give equally valid results and these are therefore described in
this part of IS0 4491.
In addition, the scope of the method has been extended to include powders
containing carbon.
If carbon is present in the powder, some metal oxides which may otherwise
have been reduced by hydrogen are instead reduced by carbon, producing
carbon monoxide or carbon dioxide. These products are not measured by
the titration with Karl Fischer reagent which is used to determine the
amount of water produced. Consequently a lower result will be obtained for
the hydrogen-reducible oxygen content.
This interference is eliminated by passing the gases emerging from the
reduction furnace over a catalyst which converts the CO and CO2 formed
into methane and water, in accordance with the following equations:
CO + 3H, + CH, -I- Hz0
CO, + 4H, + CH, + 2H,O
The conversion reaction is carried out at 380 OC over a nickel catalyst.
NOTE - Certain oxides may be partially reduced by carbon which othemvise
would not be reduced by hydrogen. In such cases the interpretation of results
should be made with great care [see IS0 4491-I :I 989, subclause 4.1.2 d)].
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IS0 4491=3:1997(E)
INTERNATIONAL STANDARD @ IS0
Determination of oxygen content
Metallic powders -
by reduction methods -
Part 3:
Hydrogen-reducible oxygen
1 Scope
This part of IS0 4491 specifies a method for the determination of the hydrogen-reducible oxygen content of metallic
powders containing 0,05 % (m/m) to 3 % (m/m) oxygen.
The method is applicable to unalloyed, partially alloyed or completely alloyed metal powders and also to mixtures of
carbides and binder metal. It is not applicable to powders containing lubricants or organic binders.
The method may be extended to powders containing carbon by the use of a special catalytic device.
This part of IS0 4491 shall be read in conjunction with IS0 760 and IS0 4491-I.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this part of
IS0 4491. At the time of publication, the editions indicated were valid. All standards are subject to revision, and
parties to agreements based on this part of IS0 4491 are encouraged to investigate the possibility of applying the
most recent editions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid
International Standards.
IS0 760:1978, Determination of water - Karl Fischer method (General method).
IS0 4491-I :I 989, Metallic powders - Determination of oxygen content by reduction methods Pat? I: General
guidelines.
3 Principle
Pre-treatment of a test portion by drying at low temperature (170 “C) in dry nitrogen or argon.
Reduction in a stream of pure dry hydrogen at a given temperature. Absorption in methanol of the water formed by
reaction of oxides with hydrogen. Titration with Karl Fischer reagent, the end-point being determined either visually
by the colour change or electrometrically with two electrodes (deadstop end-point).
For powders containing carbon, conversion of the carbon monoxide and carbon dioxide formed to methane and
water at 380 OC by means of a nickel catalyst.
@ IS0
IS0 4491-3: 1997(E)
4 Reagents
During the analysis, use only reagents of recognized analytical grade and only distilled water or water of equivalent
purity.
WARNING - Karl Fischer reagent contains four toxic compounds: iodine, sulfur dioxide, pyridine and
methanol. lt is important to avoid direct contact and especially inhalation. Following accidental spillage,
rinse with plenty of water.
4.1 Methanol, anhydrous.
42 . Karl Fischer reagent, equivalent to 1 mg of oxygen per millilitre.
Determine the titre of the Karl Fischer reagent by one of the following methods:
a) Add to the titration flask 20 mg to 30 mg of water, weighed to the nearest 0,l mg.
b) Add 100 mg to 200 mg, weighed to the nearest 0,l mg, of sodium tartrate dihydrate [certified material
containing theoretically 1566 % (m/m) of water, corresponding to 13,92 % (m/m) of oxygen], previously ground
to fine powder and dried at 105 OC + 5 OC to constant mass.
c) Use the method described in clause 7, taking 100 mg to 200 mg of pure sodium tartrate dihydrate, weighed to
the nearest 0,l mg, as the test portion, but limiting the procedure to the drying step at 170 OC and the
subsequent titration.
See IS0 760 for detailed procedures of standardization.
4.3 Hydrogen, having a maximum oxygen content of 0,005 % (m/m) and a dew point not exceeding - 45 OC.
44 Nitrogen or argon, having a maximum oxygen content of 0,005 % (m/m) and a dew point not exceeding - 45 OC.
.
4.5 Desiccant, consisti ng of granu lar an hydro us aluminium sodium silicate, activated silica gel or magnesium
perchlorate.
5 Apparatus
NOTE - The alternative arrangements of the apparatus are shown in figure 1 (method 1) and figure 2 (method 2)
respectively.
5.1 Hydrogen supply unit (A), fitted with a pressure-regulating valve, a flow control valve and a flow meter.
5.2 Purifier (B), for the hydrogen, containing a catalytic deoxidizer and a dryer.
5.3 Nitrogen (or argon) supply unit (C), fitted with a pressure-regulating valve, a flow control valve and a flow
meter.
5.4 Gas-selection valve (D).
@ IS0
IS0 4491=3:1997(E)
Key:
A ‘92 suppiy unit (5.11
B Purifier 45.2)
C N2 (or argon) supply unit (5.3)
D Gas-selection valve (5.4)
E Final gas drying unit (5.5%
F Reduction tube (5.6)
G Furnace (5.7)
H Boat 45.8)
1 Catalytic converter (5.971
J By-pass circuit (5.10)
K Titration flask (5.11)
L End-point detector 15.12)
M Burette (5.13)
f i
r
Figure 1 - Schematic arrangement of the apparatus for method 1
Key:
A H2 supply unit (5.1)
B Purifier (5.2)
?
C N2 (or argon) supply unit (5.3)
.
D Gas-selection valve (5.4)
.
E Final gas drying unit (5.5)
0 }, ;
F Reduction tube (5.6)
A B
G Furnace (5.7)
L
H Boat (5.8)
I Catalytic converter (5.9)
J By-pass circuit (5.10)
K Titration flask (5.11)
L End-point detector (5.12)
M
M Burette (5.13)
C
E
?
Figure 2 - Schematic arrangement of the apparatus for method 2
@ IS0
IS0 4491-3: 1997(E)
.
5.5 Final gas drying unit (E), containing desiccant (4.5).
5.6 Reduction tube (F), gas-tight, made of quartz or refractory material (for example dense alumina), meeting
one of the following sets of specifications:
a) A tube closed at one end with an internal diameter of 27 mm to 30 mm and a length of about 400 mm with two
smaller quartz tubes of diameter 5 mm to 6 mm and lengths 60 mm to 80 mm and 200 mm to 240 mm,
respectively, arranged as shown in figure 3. This arrangement is inserted into the first drying furnace and then
into the reduction furnace.
b) An open-ended tube with an internal diameter of about 20 mm, a length of 1 m, and a gas inlet and outlet. This
tube is permanently inserted in the two furnaces
5.7 Two furnaces (G), one for drying the test portion and the other for oxide reduction, with temperature control
systems capable of maintaining the temperature in the part of the tube containing the boat (5.8) within the specified
temperature tolerances.
NOTE - If available, one furnace combining both these functions may be used.
5.8 Boat (H), preferably of high-alumina ceramic, with a polished surface and of a suitable size such that no more
than half is filled by the test portion. The boat shall be conditioned in hydrogen at 900 “C to 1 100 OC for at least 1 h
and stored in a desiccator before use.
5.9 Catalytic converter (I), comprising a glass tube filled with a nickel catalyst, and a furnace with temperature
control system capable of maintaining the temperature in the glass tube at 380 “C. The catalyst shall be kept
permanently under hydrogen.
5.10 By-pass circuit (J), u
...
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